Question

我的数据库看起来像这样

数据：

ID | Number | A | Version
1  |  N123  | K |    1
2  |  N123  | O |    1
3  |  N123  | O |    2
4  |  N123  | K |    2
5  |  N234  | K |    1
6  |  N234  | O |    1
7  |  N456  | K |    1
8  |  N456  | L |    1
9  |  N456  | K |    2
10 |  N456  | L |    2

我的结果应如下所示：

Number |  A   | Version
N123   | O, K |    2
N234   | O, K |    1
N456   | K, L |    2

这意味着我有一个表格，其中包含与数字（和版本）相关的重复条目。例如：N123在版本1中存在两次。一次是A = K，一次是A = O.合并我有N123（V1），K = A和O.此捆绑包在版本2中有重复。我要查询的是最高版本和K的组合，以便我不再有重复的条目。

顺便提一下，数据是来自更大数据源的查询的结果。也许解决方案可以在这个初始查询中：

SELECT Data.[Number], Data.[Version], Data.[K]
FROM Data
WHERE (((Data.[Number]) In (SELECT [Number] FROM [Data] As Tmp GROUP BY [Number],[Version] HAVING Count(*)>1  And [Version] = [Data].[Version])))
ORDER BY Data.[Number], Data.[Version];

Answer 1

使用GROUP_CONCAT和CONCAT函数以及MAX和GROUP BY来实现此目标。

SELECT Number, 
GROUP_CONCAT(A) AS A,
MAX(Version) AS Version
FROM data
WHERE CONCAT(Version,'-',Number) IN (SELECT CONCAT(MAX(Version),'-',Number) FROM data GROUP BY Number)
GROUP BY Number
ORDER BY Number

输出

Number  A    Version
N123    O,K  2
N234    K,O  1
N456    K,L  2

SQL小提琴：http://sqlfiddle.com/#!9/c556b6/40/0

Answer 2

当我在评论中说，为了OleDb目的没有解决方案，我假设[A]包含一些未知（和无限）的可能性。但是，如果[A]实际上是枚举，则可以在没有自编函数帮助的情况下使用SQL在MS Access中实现串联。您可以使用一系列LEFT JOINS来执行此操作：

SELECT Number, ConcatKLO, MAX(version) AS MaxVersion FROM
(SELECT number, version, left(ConcatA,Len(ConcatA) -2) as ConcatKLO FROM
(SELECT d.number, d.version, IIF(k.A IS NULL, "",k.A + ", ")  + IIF(l.A IS NULL, "",l.A + ", ")  + IIF(o.A IS NULL, "",o.A + ", ") AS ConcatA FROM
(((SELECT DISTINCT number, version FROM Data) as d
LEFT JOIN
(SELECT number, A, version FROM Data WHERE A = 'K') as k
ON d.number = k.number and d.version = k.version)
LEFT JOIN
(SELECT number, A, version FROM Data WHERE A = 'O') as o
ON d.number = o.number and d.version = o.version)
LEFT JOIN
(SELECT number, A, version FROM Data WHERE A = 'L') as l
ON d.number = l.number and d.version = l.version) as c) as a
GROUP BY Number, concatklo

来自OleDB的调用问题是，您只能使用Access引擎中内置的函数。

访问：将条目与重复字段

2 个答案: